from heapq import *

n, a, b = map(int, input().split())
S = input()
S = S.replace("con", "*")
lst = []
row = 0
for s in S:
    if s == "*":
        row += 1
    else:
        if row != 0:
            lst.append(row)
        row = 0
if row != 0:
    lst.append(row)
lst.sort()
tot = sum(lst)

c = 0
d = 0
C = []
for l in lst:
    c += l // a
    l %= a
    d += l // b
    l %= b
    C.append(-l)
C.sort()

def ok(x):
    aa = (x + 1) // 2
    bb = x - aa

    ab = aa * a + bb * b
    if ab > tot:
        return False
    
    if c < aa:
        return False
    elif d >= bb:
        return True
    
    cc = c - aa
    dd = bb - d

    hq = C[:]
    
    for _ in range(cc):
        
        k = -heappop(hq)
        k += a
        dd -= k // bb
        k %= bb
        if dd <= 0:
            return True
        k %= b
        heappush(hq, -k)


    return dd <= 0



l = 0
r = n + 1
while r - l > 1:
    mid = (l + r) // 2
    if ok(mid):
        l = mid
    else:
        r = mid
print(l)